• 한국작물학회지
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• 제39권5호
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• pp.437-443
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• 1994

벼의 생산비 절감을 위한 성력재배의 측면에서 전국적으로 확대 실시 보급되고 있는 건답 직파재배 안전성을 기후적으로 검토하고자 출아 조한의 파종기 결정에 대한 유효기준온도인 일평균기온 1$0^{\circ}C$ 출현초일과 80% 출현시기를 지역별로 분석한 결과, 가. 연차간('73~'92, 20년간) 변이는 일수로서는 약 20~30일, 표준편차(SD)로는 약 5~7일의 차이가 있었고, '88년 이후는 평균 출현초일보다 빨라져 영농면에서 큰 관심이 되고 있음. 나. 지역별 분포(기상청 관측의 56개 지점 분석)는 북부(대관령, 5월 1일)와 남부(부산, 3월 30일)간에는 약 30일 이상의 출현시기에 차이가 있어 우리나라의 기후자원량 분석의 필요성을 느낄 수 있음. 다. 일평균기온 1$0^{\circ}C$ 평균 출현초일은 80% 출현 시기보다 약 10일 정도 빠른 경향이며 라. 19개의 수도재배농업기후지대별 평균 출현초일과 80% 출현시기의 유사성을 중심으로 다시 단순화시켜 구분하면 19개 지대는 7개의 유형으로 구분할 수 있었음.

• 한국작물학회지
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• 제44권3호
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• pp.236-242
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• 1999

To examine the seedling stand and growth as affected by early seeding dates of dry direct seeded rice in the Honam plain area of Korea, Dongjinbyeo was seeded at six seeding dates from early March to late April in rice fields of silty loam soil(Jeonbuk series) at the National Honam Agricultural Experiment Station (NHAES) for two years, 1996 and 1998. Seedling stand decreased slightly. with an early seeding date, but it produced more than the optimum seedling number except for the seeding of 25 March in 1996. Days to emergence was significantly longer, as seeding date was earlier, and days to emergence by early seeding was shortened only by 8 days because the mean air temperature was lower in 1996 than average, while in 1998, the reduction effect was nine to twenty five days because the mean air temperature was higher than average. In early seeding, various weeds occurred at the emergence date of rice and dominant weeds were Alopecurus aequailis, Ludwigia prostata and Rorippa islandica. NH$_4$$^{+}$ -N content in the soil at the 5th leaf stage and maximum tillering stage were lower, as the seeding date was earlier when nitrogen was split applied as basal and top dressed in 1996, while it was not significantly different among seeding dates when nitrogen was intensively applied as a top dressing in 1998. Tiller number at the maximum tillering stage and panicle number/m$^2$ were more, as seeding date was earlier in 1996, while it was not different in 1998. Filled grain rate and 1,000 grain weight was not different among the seeding dates. Milled rice yield was significantly decreased in the seeding before the middle of March, but in the seeding after late March, it was not varied when compared with the normal seeding date in 1996, while in 1998, there was no difference among seeding dates. From the above results, in consideration of seedling stand, weed occurance, rice growth and milled rice yield, the critical optimum early seeding time in the southern plain area may lie in early April. But it was suggested that when soil moisture is proper for seeding practices, seeding amount is increased and nitrogen is applied after plumule emergence of rice, milled rice yield may not be reduced in the seeding of middle or late March, compared with the seeding in April.l.

• 한국작물학회지
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• 제47권4호
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• pp.286-291
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• 2002

Seedling establishment of soybean [Glycine max (L.) Merr.] is a critical factor in production system and cultural practices. The objective of this study was to identify the components of soybean seedling developments encompassing planting dates and cultivars that respond to emergence, early growth stage and dry matter accumulation. Three soybean cultivars, Hwangkeumkong, Shinpaldalkong 2, and Pungsannamulkong, were planted at Baegsan silty loam soil. Planting date was May 13, June 3, and June 24 in 2001. Sprinkler irrigation was accompanied with 30mm after seeding for three planting dates. Soybean seedlings were sampled at the growth stages from VE to V5. Days to emergence of soybean seedlings were taken 8 at May 13 and 5 at June 24 plantings. Emergence percentage was over 90 at three planting dates. May 13 planting took 33 days and June 24 planting was 25 days for reaching V5 growth stage. Cotyledon number was decreased after V2. Significant cultivar difference was found in cotyledon dry weight until V2 which differed in seed dry weights at the planting times. Leaf and total dry weights of soybean seedlings were not differed from V1 to V3 among planting dates and cultivars. Leaf water contents were generally ranged 78 to 85%. Branch was appeared from V4. Leaf/stem ratio among cultivars was similar at five growth stages and gradually increased from 2.1 at V1 to 2.8 at V5. The results based on this experiment indicated that seedling establishment of soybean was continued from VE to V3 growth stages affecting mainly by planting date and soil moisture.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.103-103
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• 2017

Vigorous root growth at the seedling stage in dry direct-seeded conditions is considered as a critical trait because it is involved in seedling emergence, early vegetative vigour, nutrient uptake as well as drought tolerance. In this study, we performed QTL mapping using the recombinant inbred lines obtained from the cross between Tongil-type Dasan and temperate japonica TR22183 (DT-RILs) to identify QTL underlying early root development. TR22183, which was previously reported to have high nitrogen utility and cold tolerance, showed vigorous root growth at the seedling stage in semi-drought conditions. Root length, fresh weight and dry weight of TR22183 were significantly higher than in Dasan. By QTL analysis with genotyping-by-sequencing method, we identified two QTLs for root fresh weight (RFW) in chromosome 7 and root dry weight (RDW) in chromosome 8, explaining phenotypic variances of 13.5% and 10.6%, respectively. These QTLs would be used to develop rice varieties adapted to direct-seeded cultivating system.